Centrifugal pumps to raise water or other liquids are, of course well known, but generally they are not particularly efficient as they operate within the liquid to be raised and are, therefore, subject to considerable drag.
It is also known that water can be raised by entraining air in water falling from a considerable height, such as a waterfall, and compressing that air within a chamber at the bottom of the fall thereby creating a hydrostatic pressure in an outlet tube which forces the water upwardly. In the alternative the entrained and entrapped air can be used as a source of compressed air for driving equipment such as rock drills. One such device has been operating on this principle in Cobalt, Ontario, since 1910. This device is not particularly efficient and relies for its success upon ready availability of relatively large volumes of water with a large head, the potential energy of which would otherwise be wasted.